British Foreign Secretary Philip Hammond (2nd r.), US Secretary of State John Kerry, (r.), and European Union High Representative for Foreign Affairs and Security Policy Federica Mogherini (l.) talk to Iranian Foreign Minister Mohammad Javad Zarif as they wait for Russian Foreign Minister Sergey Lavrov, not pictured, for a group picture at the Vienna International Center in Vienna, Austria.

Beirut, Lebanon — A renewed diplomatic push to find a political solution to Syria’s bloody civil war is getting underway in Vienna Thursday evening with international players joined for the first time by Iran, a recognition of the Islamic Republic’s influential role with President Bashar al-Assad’s regime.

Central to the negotiations will be the fate of Mr. Assad himself, with Russia reportedly recommending holding early presidential elections at which the president could seek to renew his mandate or choose not to contest.

The shape of a political process to resolve the war remains unclear, however, given the wide divergence of views from the pro- and anti-Assad parties. Some analysts add that Russia’s recent military initiative may have the unintended consequence of making Assad’s foes less likely to compromise.

Syria’s war, now in its fifth year, has left a quarter of a million people dead, engulfed its neighbors and Europe in the worst refugee crisis since World War II, and so far confounded all political and diplomatic efforts to reach a solution.

The latest round of diplomacy comes against the backdrop of Russia’s military intervention in Syria, which began some two months ago with a buildup of aircraft and troops in western Syria to help defend the Assad regime.

Russian President Vladimir Putin “is attempting to secure territory for Assad as a backdrop for a diplomatic process based on the Assad regime,” says Andrew Tabler, a Syria expert at the Washington Institute for Near East policy.

“Sometimes, Russian officials say Assad can go in favor of another regime figure. Sometimes, they say Assad stays,” Mr. Tabler says. “Either way, it doesn't seem a viable whole-country solution,” he adds, noting the limited control the Assad regime has over Syrian territory.

A series of regime ground offensives in northwest Syria that began in early October has failed to make much headway against the anti-Assad rebels, despite the addition of Iranian troops and daily Russian air strikes.

Stalling offensives undermine Russia

Rebel groups in the northern Hama province, some of them armed with newly-supplied TOW anti-tank missiles, have blunted the Syrian Army’s offensive and even captured two villages that were under regime control. In Aleppo province, the Syrian Army and its allies seized ground in an advance two weeks ago. But the offensive has since slowed, and a counter-attack by the Islamic State, which controls territory to the east of Aleppo, now threatens to sever the regime’s sole transport link to the city.

“Recent intensifications in Russian and Iranian support to the Syrian regime may not be sufficient to force a rapid change in the dynamics of the Syrian civil war,” concluded an analysis released Wednesday by the Washington-based Institute for the Study of War.

The stalling Syrian Army ground offensives could undermine Russia’s ability to push for a political outcome favorable to itself and its allies in Tehran and Damascus and conversely encourage the Syrian opposition and its backers to dig in their heels.

In the initial round of talks scheduled for Thursday evening, Mr. Kerry was to be joined by his counterparts from Russia, Saudi Arabia, and Turkey. On Friday, the talks will expand to include Iran, Britain, the European Union, Lebanon, Egypt, France, Germany, and Italy. It is unclear if representatives of the Syrian government and opposition will attend.

Fayez Sarah of the opposition Syrian National Council rejected Iran’s participation in the Vienna talks, accusing it of being a “partner to the Assad regime in killing Syrians as well as occupying parts of Syrian territory through its affiliated militias.”

Russians 'genuinely irritated by Assad'

One of the biggest stumbling blocks so far has been deciding what to do with Assad. The Syrian opposition, Saudi Arabia, Turkey, and the West in general have insisted that Assad must go and that there can be no solution to the war while he remains in office.

Lately, the US and the Europeans have dialed back a little, suggesting that Assad could remain in Damascus during a transitional process. Russia and Iran, however, argue that Assad is the elected head of state and should remain in power. Last week, in a surprise move, Assad visited Putin in Moscow, his first overseas trip since the war began in 2011.

Still, analysts say Moscow’s continued support for Assad is not necessarily guaranteed.

“They are genuinely irritated by Assad and his stubbornness and unwillingness to take steps that could have eased tensions in the country,” says Nikolay Kozhanov, a fellow at the Russia and Eurasia program at the London-based Chatham House and nonresident fellow at Carnegie Moscow Center.

“The Russians do not trust Assad and would like to replace him… but they also understand that it’s impossible to replace him right now.”

Preparing Syria for elections

Still, Russia is reportedly recommending constitutional reforms and an early presidential election in Syria, which could rejuvenate Assad’s mandate (he won an election last year with 89 percent of the vote, although it went unrecognized by the US, the EU, and the Gulf Cooperation Council). On the other hand, a new election could offer Assad an opportunity to step aside in a face-saving gesture that could open up space for a political solution to the conflict.

“What I would not rule out is the possibility that all concerned may commit themselves to a series of steps aimed at preparing Syria for an eventual presidential election, one that Bashar al-Assad might commit not to contest,” says Fred Hof, senior fellow at the Atlantic Council’s Rafik Hariri Center for the Middle East.

Such a deal could allow for a series of preparatory confidence-building steps to de-escalate the conflict such as prisoner releases, the lifting of sieges, and the provision of humanitarian aid. But full implementation of such a deal “would be almost entirely in the hands of Russia, Iran, and the Assad regime … [which] does not inspire confidence that Syria will transition seamlessly from Assad clan rule to something decent,” Mr. Hof says.

“Most fundamentally, I do not see why Moscow and Tehran would want to give up Bashar,” he added. “What pressure do they face to do so?”